In the trucking industry, it is known to equip a truck trailer with one or more liftgates for cargo handling. In one type of arrangement, the liftgate may be mounted to a subframe on the underside of the trailer at a rear or side door location of the trailer. The liftgate includes a platform for supporting cargo and an actuated linkage for moving the platform through various positions relative to the trailer, including (i) a storage position under the trailer, (ii) a raised position outside the trailer adjacent the trailer door, wherein the platform is approximately coplanar with a floor of the trailer, and (iii) a lowered position outside the trailer at ground level below the raised position. The actuated linkage may be a hydraulically-powered linkage capable of lifting heavy loads, for example loads on the order of 4,000 pounds.
In the case of a liftgate mounted at a side door of a trailer, commonly referred to as a “sideloader,” imbalance during loading and unloading of heavy cargo loads poses a safety issue. The trailer will tilt toward the side of the load, which may cause cargo in the trailer and cargo on the liftgate platform to slide in a manner that may endanger nearby personnel. Because of this, it is known to provide an extendable stabilizer leg on the underside of the truck trailer adjacent the side-loading liftgate. The stabilizer leg, which is normally retracted when not in use, may be selectively extended downward to engage the ground near the side-loading liftgate to prevent the trailer from tilting when the liftgate is in use.
Despite the availability of stabilizer legs, safety challenges remain. For example, an operator may forget to deploy the stabilizer leg prior to moving cargo onto the liftgate platform from the ground during loading, or moving cargo out of the trailer onto the liftgate during unloading. Failure to extend the stabilizer leg is more likely to happen when the operator is in a hurry to load and/or unload the trailer.
Another problem associate with stabilizer legs is that the operator may forget to retract the stabilizer leg after using the liftgate. While the liftgate itself may be properly stored, the operator may not notice that the stabilizer leg remains deployed, and the operator may start driving while the stabilizer leg is still extended. This can cause expensive damage to the trailer, and may pose safety risks to vehicles and persons behind the trailer.
What is needed is a stabilizer leg that is always extended when the liftgate is placed into service, and that is always retracted when the liftgate is returned to storage.